Abstract

To evaluate the efficacy and safety of etanercept treatment in adult patients with moderate to severe rheumatoid arthritis (RA) who failed to respond (primary failure) or lost a satisfactory response (secondary failure) to adalimumab.

All patients discontinued prior adalimumab treatment and continued methotrexate with etanercept 50 mg once weekly for 24 weeks. The primary study endpoint was American College of Rheumatology 20% improvement criteria (ACR20) at week 12.

Eighty-five patients (mean age 56.6 years; female 80.0%) were evaluated for safety and 84 for efficacy. Thirty (35.7%) patients achieved ACR20 at week 12; the lower bound of the 95% confidence interval (CI; 25.6, 46.9) was greater than the prespecified goal of 24% based on previous research. Improvements from baseline in clinical outcomes and patient-reported outcomes were observed at each study visit. In planned subgroup analyses, patients with anti-adalimumab antibodies and secondary adalimumab failure had the highest ACR20 response to etanercept at week 12 (11/17 patients; 64.7%). Among the patients with secondary adalimumab failure, those with anti-adalimumab antibodies were fivefold more likely to have an ACR20 response to etanercept than those without anti-adalimumab antibodies (odds ratio 5.2; 95% CI 2.0, 13.5;
P < 0.001). Adverse events were reported for 62 (72.9%) patients and were consistent with previous studies of etanercept. Most adverse events were mild or moderate in severity.

Switching to etanercept is a therapeutic option in patients with RA who fail adalimumab treatment. The presence of anti-adalimumab antibodies may provide additional support for switching to etanercept, particularly in patients with secondary adalimumab failure.